Renewal through Participation in Global Food Security Governance: Implementing the International Food Security and Nutrition Civil Society Mechanism to the Committee on World Food Security

The food commodity price rises from 2006 to 2008 engendered a period of political renewal and reform in the governance of global food security. The Committee on World Food Security (CFS) was designated as the main international forum dealing with food security and nutrition in 2009 as part of this reform. Through the CFS reform process, civil society organizations secured the right to co-ordinate autonomously their engagement in the Committee as official participants and are doing so through the International Food Security and Nutrition Civil Society Mechanism (CSM). The CSM is an innovative institutional form designed to allow a broad range of civil society organizations from different regions of the world and from diverse constituencies, notably those who face food insecurity on a regular basis, to participate in global food security governance. The challenges and complexities of setting up and operationalizing the CSM are presented and illustrated. These findings are considered in the context of the longer-term move towards widening participation in global governance, with a particular focus on the trajectory of civil society participation in food security governance. The broad neo-liberal logic, or embedded neo-liberalism, that underpins contemporary world politics provides boundaries within which the innovative CSM is being given shape through the political agency of the participating civil society organizations. The study concludes by suggesting that while the Civil Society Mechanism faces some internal challenges, these are not insurmountable, and that the CSM represents an effective politicizing, engaging and connecting model for food-focused civil society organization entering into global governance

An Accelerated Multiboson Algorithm for Coulomb Gases with Dynamical Dielectric Effects

A recent reformulation [1] of the problem of Coulomb gases in the presence of a dynamical dielectric medium showed that finite temperature simulations of such systems can be accomplished on the basis of completely local Hamiltonians on a spatial lattice by including additional bosonic fields. For large systems, the Monte Carlo algorithm proposed in Ref. [1] becomes inefficient due to a low acceptance rate for particle moves in a fixed background multiboson field. We show here how this problem can be circumvented by use of a coupled particle-multiboson update procedure that improves acceptance rates on large lattices by orders of magnitude. The method is tested on a one-component plasma with neutral dielectric particles for a variety of system sizes.Comment: 13 pages, 2 figures, fixed typos, added reference

Non-uniform convergence of two-photon decay rates for excited atomic states

Two-photon decay rates in simple atoms such as hydrogenlike systems represent rather interesting fundamental problems in atomic physics. The sum of the energies of the two emitted photons has to fulfill an energy conservation condition, the decay takes place via intermediate virtual states, and the total decay rate is obtained after an integration over the energy of one of the emitted photons. Here, we investigate cases with a virtual state having an energy intermediate between the initial and the final state of the decay process, and we show that due to non-uniform convergence, only a careful treatment of the singularities infinitesimally displaced from the photon integration contour leads to consistent and convergent results.Comment: 3 pages; LaTe

Two-dimensional structure in a generic model of triangular proteins and protein trimers

Motivated by the diversity and complexity of two-dimensional crystals formed by triangular proteins and protein trimers, we have investigated the structures and phase behavior of hard-disk trimers. In order to mimic specific binding interactions, each trimer possesses on `attractive' disk which can interact with similar disks on other trimers via an attractive square-well potential. At low density and low temperature, the fluid phase mainly consists of tetramers, pentamers, or hexamers. Hexamers provide the structural motif for a high-density, low-temperature periodic solid phase, but we also identify a metastable periodic structure based on a tetramer motif. At high density there is a transition between orientationally ordered and disordered solid phases. The connections between simulated structures and those of 2D protein crystals -- as seen in electron microscopy -- are briefly discussed.Comment: 7 pages, 6 figure

Local Simulation Algorithms for Coulomb Gases with Dynamical Dielectric Effects

We discuss the application of the local lattice technique of Maggs and Rossetto to problems that involve the motion of objects with different dielectric constants than the background. In these systems the simulation method produces a spurious interaction force which causes the particles to move in an unphysical manner. We show that this term can be removed using a variant of a method known from high-energy physics simulations, the multiboson method, and demonstrate the effectiveness of this corrective method on a system of neutral particles. We then apply our method to a one-component plasma to show the effect of the spurious interaction term on a charged system.Comment: 13 pages, 4 figure